Once in a village lived a poor old man. He was poor so he had little money with him. One day he wanted to eat some sweets so he went to sweets shop market. There he stopped at a sweet shop and asked for some sweets. Sweet seller was cheat and tried to use short measures. Poor man noticed that and asked him not to do it. Seller smiled cunningly and said, "I was reducing load for you. so that you don't have to carry heavy load to home.."Poor man understood his trick and paid little less than the cost of sweets. Seeing less money seller complained, "You have given me less money. give me full price for sweets."Poor man replied, "But.. you see now you can save time as you have to count less.."Seller felt ashamed for his mistake and said sorry to him. 
With presence of mind one can change tricky situation in to one's own favor. 